Copolycarbonate and composition containing the same

ABSTRACT

The present invention relates to a copolycarbonate and a composition comprising the same. The copolycarbonate according to the present invention has a structure in which a specific siloxane compound is introduced in a main chain of the polycarbonate, and thus exhibits an excellent transparency and a high spiral flow while having a high impact strength at room temperature and a low melt index.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims the benefit of Korean Patent Application No.10-2014-0173005 filed on Dec. 4, 2014, Korean Patent Application No.10-2015-0105367 filed on Jul. 24, 2015 and Korean Patent Application No.10-2015-0171780 filed on Dec. 3, 2015 with the Korean IntellectualProperty Office, the disclosures of which are herein incorporated byreference in their entirety.

TECHNICAL FIELD

The present invention relates to a copolycarbonate and a compositioncomprising the same, and more specifically to a copolycarbonate beingeconomically produced, and exhibiting an excellent transparency and ahigh spiral flow while having a high impact strength at room temperatureand a low melt index, and to a composition comprising the same.

BACKGROUND OF ART

Polycarbonate resins are prepared by condensation-polymerization of anaromatic diol such as bisphenol A with a carbonate precursor such as aphosgene and have excellent impact strength, dimensional stability, heatresistance and transparency. Thus, the polycarbonate resins haveapplication in a wide range of uses, such as exterior materials ofelectrical and electronic products, automobile parts, buildingmaterials, and optical components.

Recently, in order to apply these polycarbonate resins to more variousfields, many studies have been made to obtain desired physicalproperties by copolymerizing two or more aromatic diol compounds havingdifferent structures from each other and introducing units havingdifferent structures in a main chain of the polycarbonate.

Especially, studies for introducing a polysiloxane structure in a mainchain of the polycarbonate have been undergone, but most of thesetechnologies have disadvantages in that production costs are high, and atransparency and a melt index are lowered.

Given the above circumstances, the present inventors have conductedintensive studies to overcome the above-mentioned disadvantagesencountered with the prior arts, and found that a copolycarbonate inwhich a specific siloxane compound is introduced in a main chain of thepolycarbonate as described below exhibit an excellent transparency and ahigh spiral flow while having a high impact strength at room temperatureand a low melt index. The present invention has been completed on thebasis of such a finding.

DETAILED DESCRIPTION OF THE INVENTION Technical Problem

It is an object of the present invention to provide a copolycarbonateexhibiting an excellent transparency and a high spiral flow while havinga high impact strength at room temperature and a low melt index.

It is a further object of the present invention to provide a compositioncomprising the above-mentioned copolycarbonate.

Technical Solution

In order to achieve these objects, the present invention provides acopolycarbonate comprising: an aromatic polycarbonate-based firstrepeating unit; and one or more aromatic polycarbonate-based secondrepeating units having siloxane bonds, wherein the copolycarbonate has amelt index (MI) of 3 to 10 g/10 min as measured in accordance with ASTMD1238 (300° C., 1.2 kg conditions), and a transparency of 87 to 91% asmeasured in accordance with ASTM D1003 (layer thickness of 3 mm).

Preferably, the melt index is not less than 4 g/10 min, not less than 5g/10 min, or not less than 6 g/10 min, and is not more than 9 g/10 min,or not more than 8 g/10 min.

Also, preferably, the copolycarbonate according to the present inventionhas a spiral flow of 16 to 25 cm as measured in accordance with ASTMD3123 (300° C., mold temperature of 80° C., capillary thickness of 1.5mm, holding pressure of 2000 bar). In general, polycarbonates exhibit alow spiral flow if their melt index is low. However, the copolycarbonateaccording to the present invention exhibits a high spiral flow whilehaving a low melt index as describe above. Thus, the copolycarbonateexhibiting a high spiral flow as in the present invention has excellentinjection performance during injection molding of molded articles havinglarge volume. Therefore, although the copolycarbonate has a low meltindex, it can exhibit an excellent moldability.

Preferably, the spiral flow is not less than 17 cm, or not less than 18cm, and is not more than 24 cm, not more than 23 cm, not more than 22cm, not more than 21 cm, or not more than 20 cm.

Also, preferably, the copolycarbonate according to the present inventionhas a ratio of the spiral flow and the melt index (cm/g/10 min) of 1.7to 5.0. More preferably, the ratio is not less than 1.8, not less than1.9, not less than 2.0, not less than 2.1, not less than 2.2, not lessthan 2.3, or not less than 2.4; and not more than 4.9, not more than4.8, not more than 4.7, not more than 4.6, or not more than 4.5.

In addition, the copolycarbonate according to the present invention hasa weight average molecular weight of 1,000 to 100,000 g/mol, preferably25,000 to 60,000 g/mol, or 15,000 to 35,000 g/mol. More preferably, theabove weight average molecular weight is not less than 20,000 g/mol, notless than 21,000 g/mol, not less than 22,000 g/mol, not less than 23,000g/mol, not less than 24,000 g/mol, not less than 25,000 g/mol, not lessthan 26,000 g/mol, not less than 27,000 g/mol, or not less than 28,000g/mol. Also, the weight average molecular weight is not more than 34,000g/mol, not more than 33,000 g/mol, or not more than 32,000 g/mol.

In addition, the copolycarbonate according to the present invention hasan impact strength at room temperature of 700 to 1000 J/m as measured at23° C. in accordance with ASTM D256 (⅛ inch, Notched Izod). Further,preferably, the impact strength at room temperature is not less than 750J/m, not less than 800 J/m, not less than 850 J/m, or not less than 900J/m.

Further, the copolycarbonate according to the present invention has animpact strength at low-temperature of 700 to 950 J/m as measured at −30°C. in accordance with ASTM D256 (⅛ inch, Notched Izod). Preferably, theimpact strength at low-temperature is not less than 750 J/m, or not lessthan 800 J/m.

Further, the mole ratio of the aromatic polycarbonate-based firstrepeating unit and the one or more aromatic polycarbonate-based secondrepeating units having siloxane bonds is preferably 1:0.004-0.006, andthe weight ratio thereof is preferably 1:0.04-0.07.

Further, preferably, a copolycarbonate comprising two kinds of aromaticpolycarbonate-based second repeating units having the siloxane bonds isprovided.

In particular, the aromatic polycarbonate-based first repeating unit isformed by reacting an aromatic diol compound and a carbonate precursor,and it is preferably represented by the following Chemical Formula 1:

in the Chemical Formula 1,

R₁, R₂, R₃, and R₄ are each independently hydrogen, C₁₋₁₀ alkyl, C₁₋₁₀alkoxy, or halogen,

Z is C₁₋₁₀ alkylene unsubstituted or substituted with phenyl, C₃₋₁₅cycloalkylene unsubstituted or substituted with C₁₋₁₀ alkyl, O, S, SO,SO₂, or CO.

Preferably, R₁, R₂, R₃, and R₄ are each independently hydrogen, methyl,chloro, or bromo.

Further, Z is preferably a linear or branched C₁₋₁₀ alkyleneunsubstituted or substituted with phenyl, and more preferably methylene,ethane-1,1-diyl, propane-2,2-diyl, butane-2,2-diyl,1-phenylethane-1,1-diyl or diphenylmethylene. Further, preferably, Z iscyclohexane-1,1-diyl, O, S, SO, SO₂, or CO.

Preferably, the repeating unit represented by Chemical Formula 1 may bederived from one or more aromatic diol compounds selected from the groupconsisting of bis(4-hydroxyphenyl)methane, bis(4-hydroxyphenyl)ether,bis(4-hydroxyphenyl)sulfone, bis(4-hydroxyphenyl)sulfoxide,bis(4-hydroxyphenyl)sulfide, bis(4-hydroxyphenyl)ketone,1,1-bis(4-hydroxyphenyl)ethane, bisphenol A,2,2-bis(4-hydroxyphenyl)butane, 1,1-bis(4-hydroxyphenyl)cyclohexane,2,2-bis(4-hydroxy-3,5-dibromophenyl)propane,2,2-bis(4-hydroxy-3,5-dichlorophenyl)propane,2,2-bis(4-hydroxy-3-bromophenyl)propane,2,2-bis(4-hydroxy-3-chlorophenyl)propane,2,2-bis(4-hydroxy-3-methylphenyl)propane,2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane,1,1-bis(4-hydroxyphenyl)-1-phenylethane,bis(4-hydroxyphenyl)diphenylmethane, andα,ω-bis[3-(o-hydroxyphenyl)propyl]polydimethylsiloxane.

As used herein, ‘derived from aromatic diol compounds’ means that ahydroxy group of the aromatic diol compound and a carbonate precursorare reacted to form the repeating unit represented by Chemical Formula1.

For example, when bisphenol A which is an aromatic did compound, andtriphosgene which is a carbonate precursor are polymerized, therepeating unit represented by Chemical Formula 1 is represented by thefollowing Chemical Formula 1-1:

The carbonate precursor used herein may include one or more selectedfrom the group consisting of dimethyl carbonate, diethyl carbonate,dibutyl carbonate, dicyclohexyl carbonate, diphenyl carbonate, ditolylcarbonate, bis(chlorophenyl)carbonate, di-m-cresyl carbonate, dinaphthylcarbonate, bis(diphenyl)carbonate, phosgene, triphosgene, diphosgene,bromo phosgene and bishalo formate. Preferably, triphosgene or phosgenemay be used.

The one or more aromatic polycarbonate-based second repeating unitshaving siloxane bonds is formed by reacting one or more siloxanecompounds and a carbonate precursor, and it comprises preferably arepeating unit represented by the following Chemical Formula 2 and arepeating unit represented by the following Chemical Formula 3:

in the Chemical Formula 2,

each of X₁ is independently C₁₋₁₀ alkylene,

each of R₅ is independently hydrogen; C₁₋₁₅ alkyl unsubstituted orsubstituted with oxiranyl, oxiranyl-substituted C₁₋₁₀ alkoxy, or C₆₋₂₀aryl; halogen; C₁₋₁₀ alkoxy; allyl; C₁₋₁₀ haloalkyl; or C₆₋₂₀ aryl, and

n is an integer of 10 to 200,

in the Chemical Formula 3,

each of X₂ is independently C₁₋₁₀ alkylene,

each of Y₁ is independently hydrogen, C₁₋₆ alkyl, halogen, hydroxy, C₁₋₆alkoxy, or C₆₋₂₀ aryl,

each of R₆ is independently hydrogen; or C₁₋₁₅ alkyl unsubstituted orsubstituted with oxiranyl, oxiranyl-substituted C₁₋₁₀ alkoxy, or C₆₋₂₀aryl; halogen; C₁₋₁₀ alkoxy; allyl; C₁₋₁₀ haloalkyl; or C₆₋₂₀ aryl, and

m is an integer of 10 to 200.

In Chemical Formula 2, each of X₁ is independently preferably C₂₋₁₀alkylene, more preferably C₂₋₄ alkylene and most preferablypropane-1,3-diyl.

Also, preferably, each of R₅ is independently hydrogen, methyl, ethyl,propyl, 3-phenylpropyl, 2-phenylpropyl, 3-(oxiranylmethoxy)propyl,fluoro, chloro, bromo, iodo, methoxy, ethoxy, propoxy, allyl,2,2,2-trifluoroethyl, 3,3,3-trifluoropropyl, phenyl, or naphthyl. Inaddition, each of R₅ is independently preferably C₁₋₁₀ alkyl, morepreferably C₁₋₆ alkyl, still more preferably C₁₋₃ alkyl and mostpreferably methyl.

Further, preferably, n is an integer of not less than 10, not less than15, not less than 20, not less than 25, not less than 26, not less than27, or not less than 28; and not more than 50, not more than 45, notmore than 40, not more than 35, not more than 34, or not more than 33.

In Chemical Formula 3, each of X₂ is independently preferably C₂₋₁₀alkylene, more preferably C₂₋₆ alkylene and most preferably isobutylene.

Further, preferably, Y₁ are hydrogen.

Further, preferably, each of R₆ is independently hydrogen, methyl,ethyl, propyl, 3-phenylpropyl, 2-phenylpropyl,3-(oxiranylmethoxy)propyl, fluoro, chloro, bromo, iodo, methoxy, ethoxy,propoxy, allyl, 2,2,2-trifluoroethyl, 3,3,3-trifluoropropyl, phenyl, ornaphthyl. Further, each of R₆ is independently preferably C₁₋₁₀ alkyl,more preferably C₁₋₆ alkyl, still more preferably C₁₋₃ alkyl, and mostpreferably methyl.

Preferably, m is not less than 40, not less than 45, not less than 50,not less than 55, not less than 56, not less than 57, or not less than58; and not more than 80, not more than 75, not more than 70, not morethan 65, not more than 64, not more than 63, or not more than 62.

The repeating unit represented by Chemical Formula 2 and the repeatingunit represented by Chemical Formula 3 are, respectively, derived from asiloxane compound represented by the following Chemical Formula 2-1 anda siloxane compound represented by the following Chemical Formula 3-1:

in the Chemical Formula 2-1, X₁, R₅ and n are the same as previouslydefined,

in the Chemical Formula 3-1, X₂, Y₁, R₆ and m are the same as previouslydefined.

As used herein, ‘derived from a siloxane compound’ means that a hydroxygroup of the respective siloxane compound and a carbonate precursor arereacted to form the repeating unit represented by Chemical Formula 2 andthe repeating unit represented by Chemical Formula 3. Further, thecarbonate precursors that can be used for the formation of the repeatingunits represented by Chemical Formulae 2 and 3 are the same as thosedescribed for the carbonate precursor that can be used for the formationof the repeating unit represented by Chemical Formula 1 described above.

The methods for preparing the siloxane compound represented by ChemicalFormula 2-1 and the siloxane compound represented by Chemical Formula3-1 are represented by the following Reaction Schemes 1 and 2,respectively:

in the Reaction Scheme 1,

X₁′ is C₂₋₁₀ alkenyl, and

X₁, R₅ and n are the same as previously defined,

in the Reaction Scheme 2,

X₂′ is C₂₋₁₀ alkenyl, and

X₂, Y₁, R₆ and m are the same as previously defined.

In the Reaction Scheme 1 and Reaction Scheme 2, the reaction ispreferably conducted in the presence of a metal catalyst. As the metalcatalyst, a Pt catalyst is preferably used. The Pt catalyst used hereinmay include one or more selected from the group consisting of Ashbycatalyst, Karstedt catalyst, Lamoreaux catalyst, Speer catalyst,PtCl₂(COD), PtCl₂(benzonitrile)₂ and H₂PtBr₆. The metal catalyst may beused in an amount of not less than 0.001 parts by weight, not less than0.005 parts by weight, or not less than 0.01 parts by weight; and notmore than 1 part by weight, not more than 0.1 part by weight, or notmore than 0.05 part by weight, based on 100 parts by weight of thecompounds represented by the Chemical Formulae 7 or 9.

Further, the above reaction temperature is preferably 80 to 100° C.Further, the above reaction time is preferably 1 to 5 hours.

In addition, the compounds represented by Chemical Formulae 7 or 9 canbe prepared by reacting an organodisiloxane and an organocyclosiloxanein the presence of an acid catalyst, and n and m may be adjusted byadjusting the amount of the reactants. The reaction temperature ispreferably 50 to 70° C. Also, the reaction time is preferably 1 to 6hours.

The above organodisiloxane may include one or more selected from thegroup consisting of tetramethyldisiloxane, tetraphenyldisiloxane,hexamethyldisiloxane and hexaphenyldisiloxane. In addition, the aboveorganocyclosiloxane may include, for example, organocyclotetrasiloxane.As one example thereof, octamethylcyclotetrasiloxane andoctaphenylcyclotetrasiloxane and the like can be included.

The above organodisiloxane can be used in an amount of not less than 0.1parts by weight, or not less than 2 parts by weight; and not more than10 parts by weight, or not more than 8 parts by weight, based on 100parts by weight of the organocyclosiloxane.

The above acid catalyst that may be used herein includes one or moreselected from the group consisting of H₂SO₄, HClO₄, AlCl₃, SbCl₅, SnCl₄and acid clay (fuller's earth). Further, the acid catalyst may be usedin an amount of not less than 0.1 parts by weight, not less than 0.5parts by weight, or not less than 1 part by weight; and not more than 10parts by weight, not more than 5 parts by weight or not more than 3parts by weight, based on 100 parts by weight of theorganocyclosiloxane.

In particular, by adjusting the content of the repeating unitrepresented by Chemical Formula 2 and the repeating unit represented byChemical Formula 3, the impact resistance at low-temperature and meltindex of the copolycarbonate can be improved simultaneously. Preferably,the weight ratio between the repeating units may be from 1:99 to 99:1.Preferably, the weight ratio is from 3:97 to 97:3, from 5:95 to 95:5,from 10:90 to 90:10, or from 15:85 to 85:15, and more preferably from20:80 to 80:20. The weight ratio of the above repeating unitscorresponds to the weight ratio of siloxane compounds, for example thesiloxane compound represented by Chemical Formula 2-1 and the siloxanecompound represented by Chemical Formula 3-1.

Preferably, the repeating unit represented by Chemical Formula 2 isrepresented by the following Chemical Formula 2-2:

in the Chemical Formula 2-2, R₅ and n are the same as previouslydefined. Preferably, R₅ is methyl.

Also, preferably, the repeating unit represented by Chemical Formula 3is represented by the following Chemical Formula 3-2:

in the Chemical Formula 3-2, R₆ and m are he same as previously defined.Preferably, R₆ is methyl.

Further, preferably, the copolycarbonate according to the presentinvention comprises all of the repeating unit represented by ChemicalFormula 1-1, the repeating unit represented by Chemical Formula 2-2, andthe repeating unit represented by Chemical Formula 3-2.

Further, the present invention provides a method for preparing acopolycarbonate comprising a step of polymerizing the aromatic diolcompound, the carbonate precursor and one or more siloxane compounds.

The aromatic diol compound, the carbonate precursor and the one or moresiloxane compounds are the same as previously described.

During the polymerization, the one or more siloxane compounds can beused in an amount of not less than 0.1% by weight, not less than 0.5% byweight, not less than 1% by weight, not less than 1.5% by weight, notless than 2.0% by weight, not less than 2.5% by weight, or more than3.0% by weight;

and not more than 20% by weight, not more than 10% by weight, not morethan 7% by weight, not more than 5% by weight or not more than 4% byweight, based on 100% by weight in total of the aromatic diol compound,the carbonate precursor and the one or more siloxane compounds. Also,the above aromatic diol compound can be used in an amount of not lessthan 40% by weight, not less than 50% by weight, or not less than 55% byweight; and not more than 80% by weight, not more than 70% by weight, ornot more than 65% by weight, based on 100% by weight in total of thearomatic diol compound, the carbonate precursor and the one or moresiloxane compounds. The above carbonate precursor can be used in anamount of not less than 10% by weight, not less than 20% by weight, ornot less than 30% by weight, and in an amount of not more than 60% byweight, not more than 50% by weight, or not more than 40% by weight,based on 100% by weight in total of the aromatic diol compound, thecarbonate precursor and the one or more siloxane compounds.

Further, as the polymerization method, an interfacial polymerizationmethod can be used as one example. In this case, there is an effect inthat the polymerization reaction is possible at a low temperature underan atmospheric pressure, and the molecular weight is easily controlled.The above interfacial polymerization is preferably conducted in thepresence of an acid binder and an organic solvent. Furthermore, theabove interfacial polymerization may comprise, for example, the steps ofconducting pre-polymerization, then adding a coupling agent and againconducting polymerization. In this case, the copolycarbonate having ahigh molecular weight can be obtained.

The materials used in the interfacial polymerization are notparticularly limited as long as they can be used in the polymerizationof polycarbonate. The used amount thereof may be controlled as required.

The acid binding agent may include, for example, alkali metal hydroxidessuch as sodium hydroxide or potassium hydroxide, or amine compounds suchas pyridine.

The organic solvent is not particularly limited as long as it is asolvent that can be usually used in the polymerization ofpolycarbonates. As one example, halogenated hydrocarbon such asmethylene chloride or chlorobenzene can be used.

Further, during the interfacial polymerization, reaction accelerators,for example, a tertiary amine compound such as triethylamine,tetra-n-butyl ammonium bromide and tetra-n-butylphosphonium bromide or aquaternary ammonium compound or a quaternary phosphonium compound may befurther used for accelerating the reaction.

In the interfacial polymerization, the reaction temperature ispreferably 0 to 40° C. and the reaction time is preferably 10 minutes to5 hours. Further, during the interfacial polymerization reaction, pH ispreferably maintained at 9 or more, or 11 or more.

In addition, the interfacial polymerization may be conducted by furtherincluding a molecular weight modifier. The molecular weight modifier maybe added before the initiation of polymerization, during the initiationof polymerization, or after the initiation of polymerization.

As the above molecular weight modifier, mono-alkylphenol may be used. Asone example, the mono-alkylphenol is one or more selected from the groupconsisting of p-tert-butylphenol, p-cumyl phenol, decyl phenol, dodecylphenol, tetradecyl phenol, hexadecyl phenol, octadecyl phenol, eicosylphenol, docosyl phenol and triacontyl phenol, and preferablyp-tert-butylphenol. In this case, the effect of adjusting the molecularweight control is great.

The above molecular weight modifier is contained, for example, in anamount of not less than 0.01 parts by weight, not less than 0.1 parts byweight, or not less than 1 part by weight, and in an amount of not morethan 10 parts by weight, not more than 6 parts by weight, or not morethan 5 parts by weight, based on 100 parts by weight of the aromaticdial compound. Within this range, the required molecular weight can beobtained.

In addition, the present invention provides a polycarbonate compositioncomprising the above-mentioned copolycarbonate and polycarbonate.

The copolycarbonate may be used alone, but it can be used together withthe polycarbonate as needed to thereby control the physical propertiesof the copolycarbonate.

The above polycarbonate is distinguished from the copolycarbonateaccording to the present invention in that a polysiloxane structure isnot introduced in a main chain of the polycarbonate.

Preferably, the above polycarbonate comprises a repeating unitrepresented by the following Chemical Formula 4:

in the Chemical Formula 4,

R′₁, R′₂, R′₃ and R′₄ are each independently hydrogen, C₁₋₁₀ alkyl,C₁₋₁₀ alkoxy, or halogen,

Z′ is C₁₋₁₀ alkylene unsubstituted or substituted with phenyl, C₃₋₁₅cycloalkylene unsubstituted or substituted with C₁₋₁₀ alkyl, O, S, SO,SO₂ or CO.

Further, preferably, the above polycarbonate has a weight averagemolecular weight of 15,000 to 35,000 g/mol. More preferably, the aboveweight average molecular weight (g/mol) is not less than 20,000, notless than 21,000, not less than 22,000, not less than 23,000, not lessthan 24,000, not less than 25,000, not less than 26,000, not less than27,000, or not less than 28,000. Further, the above weight averagemolecular weight (g/mol) is not more than 34,000, not more than 33,000,or not more than 32,000.

The repeating unit represented by Chemical Formula 4 is formed byreacting the aromatic diol compound and the carbonate precursor. Thearomatic diol compound and the carbonate precursor that can be usedherein are the same as previously described for the repeating unitrepresented by Chemical Formula 1.

Preferably, R′₁, R′₂, R′₃, R′₄ and Z′ in Chemical Formula 4 are the sameas previously described for R₁, R₂, R₃, R₄ and Z in Chemical Formula 1,respectively.

Further, preferably, the repeating unit represented by Chemical Formula4 is represented by the following Chemical Formula 4-1:

In the polycarbonate composition, the weight ratio of thecopolycarbonate and the polycarbonate is preferably from 99:1 to 1:99,more preferably from 90:10 to 50:50, and most preferably from 80:20 to60:40.

In addition, the present invention provides an article comprising theabove-mentioned copolycarbonate or the polycarbonate composition.

Preferably, the above article is an injection molded article. Inaddition, the article may further comprise, for example, one or moreselected from the group consisting of antioxidants, heat stabilizers,light stabilizers, plasticizers, antistatic agents, nucleating agents,flame retardants, lubricants, impact reinforcing agents, fluorescentbrightening agents, ultraviolet absorbers, pigments and dyes.

The method for preparing the article may comprise the steps of mixingthe copolycarbonate according to the present invention and additivessuch as antioxidants using a mixer, extrusion-molding the mixture withan extruder to produce a pellet, drying the pellet and then injectingthe dried pellet with an injection molding machine.

Advantageous Effects

As set forth above, according to the present invention, thecopolycarbonate in which a specific siloxane compound is introduced in amain chain of the polycarbonate has characteristics of providing anexcellent transparency and a high spiral flow.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Below, preferred embodiments will be provided to assist in theunderstanding of the invention. However, these examples are providedonly for illustration of the present invention, and should not beconstrued as limiting the present invention by the examples.

PREPARATION EXAMPLE 1 Preparation of Polyorganosiloxane (AP-30)

42.5 g (142.8 mmol) of octamethylcyclotetrasiloxane and 2.26 g (16.8mmol) of tetramethyldisiloxane were mixed. The mixture was then placedin 3 L flask together with 1 part by weight of an acid clay (DC-A3)compared to 100 parts by weight of octamethylcyclotetrasiloxane, andreacted at 60° C. for 4 hours. After completion of the reaction, thereaction product was diluted with ethyl acetate and quickly filteredusing a celite. The repeating unit (n) of the unmodifiedpolyorganosiloxane thus prepared was 30 when confirmed through ¹H NMR.

To the resulting terminal-unmodified polyorganosiloxane, 9.57 g (71.3mmol) of 2-allylphenol and 0.01 g (50 ppm) of Karstedt's platinumcatalyst were added and reacted at 90° C. for 3 hours. After completionof the reaction, the unreacted polyorganosiloxane was removed byconducting evaporation under the conditions of 120° C. and 1 torr. Theterminal-modified polyorganosiloxane thus prepared was designated asAP-30. AP-30 was a pale yellow oil and the repeating unit (n) was 30when confirmed through ¹H NMR using a Varian 500 MHz, and furtherpurification was not required.

PREPARATION EXAMPLE 2 Preparation of Polyorganosiloxane (MB-60)

47.60 g (160 mmol) of octamethylcyclotetrasiloxane and 1.5 g (11 mmol)of tetramethyldisiloxane were mixed. The mixture was then introduced in3 L flask together with 1 part by weight of an acid clay (DC-A3)compared to 100 parts by weight of octamethylcyclotetrasiloxane, andreacted at 60° C. for 4 hours. After completion of the reaction, thereaction product was diluted with ethyl acetate and quickly filteredusing a celite. The repeating unit (m) of the unmodifiedpolyorganosiloxane thus prepared was 60 when confirmed through ¹H NMR.

To the resulting terminal-unmodified polyorganosiloxane, 6.13 g (29.7mmol) of 3-methylbut-3-enyl 4-hydroxybenzoate and 0.01 g (50 ppm) ofKarstedt's platinum catalyst were added and reacted at 90° C. for 3hours. After completion of the reaction, the unreacted siloxane wasremoved by conducting evaporation under the conditions of 120° C. and 1torr. The terminal-modified polyorganosiloxane thus prepared wasdesignated as MB-60. MB-60 was a pale yellow oil and the repeating unit(m) was 60 when confirmed through ¹H NMR using a Varian 500 MHz, andfurther purification was not required.

PREPARATION EXAMPLE 3 Preparation of Polyorganosiloxane (Eu-50)

47.60 g (160 mmol) of octamethylcyclotetrasiloxane and 1.7 g (13 mmol)of tetramethyldisiloxane were mixed. The mixture was then placed in 3 Lflask together with 1 part by weight of an acid clay (DC-A3) compared to100 parts by weight of octamethylcyclotetrasiloxane, and reacted at 60°C. for 4 hours. After completion of the reaction, the reaction productwas diluted with ethyl acetate and quickly filtered using a celite. Therepeating unit (n) of the terminal-unmodified polyorganosiloxane thusprepared was 50 when confirmed through ¹H NMR.

To the resulting terminal-unmodified polyorganosiloxane, 6.13 g (29.7mmol) of Eugenol and 0.01 g (50 ppm) of Karstedt's platinum catalystwere added and reacted at 90° C. for 3 hours. After completion of thereaction, the unreacted siloxane was removed by conducting theevaporation under the conditions of 120° C. and 1 torr. Theterminal-modified polyorganosiloxane thus prepared was designated asEu-50. Eu-50 was a pale yellow oil and the repeating unit (n) was 50when confirmed through ¹H NMR using a Varian 500 MHz, and furtherpurification was not required.

EXAMPLE 1

Step 1: Preparation of Copolycarbonate Resin

978.4 g of Bisphenol A (BPA), 1,620 g of NaOH 32% aqueous solution, and7,500 g of distilled water were added to 20 L glass reactor. Afterconfirming that BPA was completely dissolved under nitrogen atmosphere,3,670 g of methylene chloride, 17.5 g of p-tert-butylphenol, and 55.2 gof polyorganosiloxane previously prepared (mixture of 80% by weight ofpolyorganosiloxane (AP-30) of Preparation Example 1 and 20% by weight ofpolyorganosiloxane (MB-60) of Preparation Example 2) were added andmixed. To this mixture, 3,850 g of methylene chloride in which 542.5 gof triphosgene was dissolved was added dropwise for one hour. At thistime, a NaOH aqueous solution was maintained at pH 12. After completionof the dropwise addition, the reaction product was aged for 15 minutes,and 195.7 g of triethylamine was dissolved in methylene chloride andadded. After 10 minutes, pH was adjusted to 3 with 1 N aqueoushydrochloric acid solution and then washed three times with distilledwater. Subsequently, the methylene chloride phase was separated, andthen precipitated in methanol to give a copolycarbonate resin in theform of a powder. The molecular weight of the resulting copolycarbonateresin was measured by GPC using PC Standard and the result confirmedthat the weight average molecular weight was 30,231 g/mol.

2) Preparation of Injection-Molded Specimen

With respect to 1 part by weight of the copolycarbonate resin preparedabove, 0.050 parts by weight of tris(2,4-di-tert-butylphenyl)phosphite,0.010 parts by weight ofoctadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and 0.030parts by weight of pentaerythritoltetrastearate were added, and theresulting mixture was pelletized using a φ30 mm twin screw extruderprovided with a vent. Thereafter, a specimen was injection-molded usinga cylinder temperature of 300° C. and a mold temperature of 80° C. usingthe N-20C injection molding machine manufactured by JSW Co., Ltd.

EXAMPLE 2

The copolycarbonate resin and its injection-molded specimen wereprepared in the same method as in Example 1, except that the totalweight of polyorganosiloxane was 36.8 g (mixture of 80% by weight ofpolyorganosiloxane (AP-30) of Preparation Example 1 and 20% by weight ofpolyorganosiloxane (MB-60)).

COMPARATIVE EXAMPLE 1

The copolycarbonate resin and its injection-molded specimen wereprepared by the same method as in Example 1, except that only 36.8 g ofpolyorganosiloxane (AP-30) of Preparation Example 1 was used aspolyorganosiloxane.

COMPARATIVE EXAMPLE 2

The copolycarbonate resin and its injection-molded specimen wereprepared by the same method as in Example 1, except that only 36.8 g ofpolyorganosiloxane (Eu-50) of Preparation Example 3 was used aspolyorganosiloxane.

COMPARATIVE EXAMPLE 3

The copolycarbonate resin and its injection-molded specimen wereprepared by the same method as in Example 1, except thatpolyorganosiloxane was not used.

EXPERIMENTAL EXAMPLE Evaluation of Physical Properties

The weight average molecular weight of the resin prepared in theExamples and Comparative Examples were measured by GPC using PC Standardwith Agilent 1200 series.

The physical properties of the specimens prepared with the resins of theExamples and the Comparative Examples were measured in the followingmanner and the results were shown in Table 1 below.

-   -   Weight average molecular weight (g/mol): measured by GPC using        PC Standard with Agilent 1200 series.    -   Melt Index (MI): measured in accordance with ASTM D1238 (300°        C., 1.2kg conditions).    -   Impact strength at room temperature: measured at 23° C. in        accordance with ASTM D256 (⅛ inch, Notched Izod).    -   Impact strength at low-temperature: measured at −30° C. in        accordance with ASTM D256 (⅛ inch. Notched Izod).    -   Transparency (Tt, %): measured in accordance with ASTM D1003        (layer thickness of 3 mm). The equipment used in the measurement        and the range of measurement are as follows.    -   Equipment name: Ultra scan pro (Focus, Inc.)    -   Measurement range: 350-1050 nm    -   Repeating units: determined by 1 H-NMR using Varian 500 MHz.    -   Spiral flow: measured in accordance with ASTM D3123 (300° C.,        mold temperature of 80° C., capillary thickness of 1.5 mm,        holding pressure of 2000 bar). In addition, the value of spiral        flow was divided into the value of the melt index (MI).

TABLE 1 Impact Impact Weight strength strength Melt (Spiral average atroom at low- index Spiral flow)/ molecular temperature temperature (g/10flow (Melt weight Transparency (J/m) (J/m) min) (cm) index) (g/mol) (%)Com. 686 225 15 20 1.33 23,329 90.3 Ex. 1 Com. 802 678 10 15 1.50 26,16685.2 Ex. 2 Com. 870 194 10 16 1.60 31,312 91.3 Ex. 3 Ex. 1 925 813 6 183.00 30,231 90.6 Ex. 2 826 785 8 20 2.50 29,842 89.9

As shown in Table 1 above, the copolycarbonate according to the presentinvention (Examples 1 and 2) exhibited an excellent transparency whilemaintaining an excellent impact strength at room temperature. Further,it could be confirmed that the copolycarbonate according to the presentinvention exhibited a high spiral flow while having a low melt index(MI)compared to the Comparative Examples.

1. A copolycarbonate comprising: an aromatic polycarbonate-based first repeating unit; and one or more aromatic polycarbonate-based second repeating units having siloxane bonds, wherein the copolycarbonate has a melt index (MI) of 3 to 10 g/10 min as measured in accordance with ASTM D1238 (300° C., 1.2 kg conditions), and a transparency of 87 to 91% as measured in accordance with ASTM D1003 ((layer thickness of 3 mm).
 2. The copolycarbonate of claim 1 wherein the copolycarbonate has a spiral flow of 16 to 25 cm as measured in accordance with ASTM D3123 (300° C., mold temperature of 80° C., capillary thickness of 1.5 mm, holding pressure of 2000 bar).
 3. The copolycarbonate of claim 1 wherein the copolycarbonate has a ratio of the spiral flow and the melt index (MI) (cm/g/10 min) of 1.7 to 5.0.
 4. The copolycarbonate of claim 1 wherein the copolycarbonate has a weight average molecular weight of 1,000 to 100,000 g/moL
 5. The copolycarbonate of claim 1 wherein the copolycarbonate comprises two kinds of aromatic polycarbonate-based second repeating units having the siloxane bonds.
 6. The copolycarbonate of claim 1 wherein the first repeating unit is represented by the following Chemical Formula 1:

in the Chemical Formula 1, R₁, R₂, R₃ and R₄ are each independently hydrogen, C₁₋₁₀ alkyl, C₁₋₁₀ alkoxy, or halogen, Z is C₁₋₁₀ alkylene unsubstituted or substituted with phenyl, C₃₋₁₅ cycloalkylene unsubstituted or substituted with C₁₋₁₀ alkyl, O, S, SO, SO₂, or CO.
 7. The copolycarbonate of claim 6 wherein the repeating unit represented by the Chemical Formula 1 is derived from one or more aromatic diol compounds selected from the group consisting of bis(4-hydroxyphenyl)methane, bis(4-hydroxyphenyl)ether, bis(4-hydroxyphenyl)sulfone, bis(4-hydroxyphenyl)sulfoxide, bis(4-hydroxyphenyl)sulfide, bis(4-hydroxyphenyl)ketone, 1,1-bis(4-hydroxyphenyl)ethane, bisphenol A, 2,2-bis(4-hydroxyphenyl)butane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 2,2-bis(4-hydroxy-3,5-dibromophenyl)propane, 2,2-bis(4-hydroxy-3,5-dichlorophenyl)propane, 2,2-bis(4-hydroxy-3-bromophenyl)propane, 2,2-bis(4-hydroxy-3-chlorophenyl)propane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, 1,1-bis(4-hydroxyphenyl)-1-phenylethane, bis(4-hydroxyphenyl)diphenylmethane, and α,ω-bis[3-(o-hydroxyphenyl)propyl]polydimethylsiloxane.
 8. The copolycarbonate of claim 6 wherein the Chemical Formula I is represented by the following Chemical formula 1-1:


9. The copolycarbonate of claim 1 wherein the second repeating unit comprises a repeating unit represented by the following Chemical Formula 2 and a repeating unit represented by the following Chemical Formula 3:

in the Chemical Formula 2, each of X₁ is independently C₁₋₁₀ alkylene, each of R₅ is independently hydrogen; C₁₋₁₅ alkyl unsubstituted or substituted with oxiranyl, oxiranyl-substituted C₁₋₁₀ alkoxy, or C₆₋₂₀ aryl; halogen; C₁₋₁₀ alkoxy; allyl; C₁₋₁₀ haloalkyl; or C₆₋₂₀ aryl, and n is an integer of 10 to 200,

in the Chemical Formula 3, each of X₂ is independently C₁₋₁₀ alkylene, each of is independently hydrogen, C₁₋₆ alkyl, halogen, hydroxy, alkoxy, or C₆₋₂₀ aryl, each of R₆ is independently hydrogen; or C₁₋₁₅ alkyl unsubstituted or substituted with oxiranyl, oxiranyl-substituted C₁₋₁₀ alkoxy, or C₆₋₂₀ aryl; halogen; C₁₋₁₀ alkoxy; allyl; C₁₋₁₀ haloalkyl; or C₆₋₂₀ aryl, and m is an integer of 10 to
 200. 10. The copolycarbonate of claim 9 wherein the weight ratio of the repeating unit represented by Chemical Formula 2 and the repeating unit represented by Chemical For 3 is from 80:20 to 95:5.
 11. The copolycarbonate of claim 9 wherein the repeating unit represented by the Chemical Formula 2 is represented by the following Chemical Formula 2-2:


12. The copolycarbonate of claim 9 wherein the repeating unit represented by Chemical Formula 3 is represented by the following Chemical Formula 3-2:


13. The copolycarbonate of claim 1 wherein the copolycarbonate has an impact strength at low-temperature of 700 to 950 J/m as measured at −30° C. in accordance with ASTM D256 (⅛ inch, Notched Izod).
 14. The copolycarbonate of claim 1 wherein the copolycarbonate has an impact strength at room temperature of 700 to 1000 J/m as measured at 23° C. in accordance with ASTM D256 (⅛ inch, Notched Izod).
 15. A polycarbonate composition comprising the copolycarbonate according to claim 1 and a polycarbonate.
 16. The polycarbonate composition of claim 15 wherein a polysiloxane structure is not introduced in a main chain of the polycarbonate.
 17. The polycarbonate composition of claim 15 wherein the polycarbonate comprises a repeating unit represented by the following Chemical Formula 4:

in the Chemical Formula 4, R′₁, R′₂, R′₃ and R′₄ are each independently hydrogen, C₁₋₁₀ alkyl, C₁₋₁₀ alkoxy, or halogen, Z′ is C₁₋₁₀ alkylene unsubstituted or substituted with phenyl, C₃₋₁₅ cycloalkylene unsubstituted or substituted with C₁₋₁₀ alkyl, O, S, SO, SO₂ or CO. 